A transmission method of the aforementioned type is known. The STANAG-4444 standard describes a time structure comprising a first TS1 and a second TS2 time slot with permanent alternation between these two time slots when the transmission network is on standby. The first time slot TS1 is necessarily allocated to a frequency hopping transmission mode of the STANAG-4444 standard. The second time slot TS2 can be allocated to any transmission mode, in particular to another transmission mode in fixed frequency, as provided by standard STANAG 4538 describing the combined use of the STANAG-4444 standard and standards relating to fixed frequency transmission such as the MIL-STD-188-141 standard.
The frequency hopping transmission mode, FH, is generally used for half-duplex data transmission sent to all the stations, and the fixed frequency transmission mode is designed for transmitting data at a high bit rate of up to 19200 bits per second, the FH mode having a transmission rate limited to 2400 bits per second.
However, the duration of the changeover from one transmission mode to the other is particularly lengthy, which places constraints on users who therefore avoid having to change from one mode to the other but benefit less from the advantages offered by each of the transmission modes.